The High Frequency Instrument on ESA's Planck mission has completed its survey of the remnant light from the Big Bang. The sensor ran out of coolant on Saturday as expected, ending its ability to detect this faint energy.

"Planck has been a wonderful mission; spacecraft and instruments have been performing outstandingly well, creating a treasure trove of scientific data for us to work with," said Jan Tauber, ESA’s Planck Project Scientist.

Less than half a million years after the Universe was created in the Big Bang 13.7 billion years ago, the fireball cooled to temperatures of about 4000ºC, filling the sky with bright, visible light. As the Universe has expanded, that light has faded and moved to microwave wavelengths. By studying patterns imprinted in that light today, scientists hope to understand the Big Bang and the very early Universe, long before galaxies and stars first formed. Planck has been measuring these patterns by surveying the whole sky with its High Frequency Instrument (HFI) and its Low Frequency Instrument (LFI). Combined, they give Planck unparalleled wavelength coverage and the ability to resolve faint details.

Launched in May 2009, the minimum requirement for success was for the spacecraft to complete two whole surveys of the sky. In the end, Planck worked perfectly for 30 months, about twice the span originally required, and completed five full-sky surveys with both instruments.

With funding from the Canadian Space Agency, Canada contributed to the HFI mainly through development of sophisticated analysis software for studying the complex data streams from the satellite, developed at the University of Toronto.